An investigation has started into allegations that a U.S. spy agency inappropriately listened to the overseas phone calls of hundreds of United States citizens. Among the phone conversations the agency eavesdropped on were those of United States workers and military personnel who called home to talk to their families.

The piece of information was revealed by two former military intercept officers assigned to the National Security Agency (NSA). According to their sayings, spies of the American agency have been listening on intimates overseas phone conversations on a regular basis and even shared the recordings with each other.

Spying on phone calls was done under the relaxed rules adopted by the Bush administration on the matter to facilitate spying on terrorists and prevent eventual attacks.

The eavesdropping accusations were labeled as "extremely disturbing" by Senator John D. Rockefeller IV, who added that the Senate intelligence committee which he is a chairman of has been gathering data regarding the issue and may soon hold hearings.

"Any time there is an allegation regarding abuse of the privacy and civil liberties of Americans, it is a very serious matter," the Democrat Senator said yesterday.

As part of its war on terror campaign, the Bush administration implemented a terrorist surveillance program that allows the spying agencies to intercept phone calls between the U.S. and overseas without a court order. The only condition is that one of the parties involved in the phone call is a terror suspect.

The NSA monitored the phone calls of American military personnel and those of journalists, aid workers and other staff who were calling home in the U.S. and were talking about "personal, private things with Americans who are not in any way, shape or form associated with anything to do with terrorism," said Adrienne Kinne, a former U.S. Army Reserves Arab linguist, ABC News reported.